Molly McCanta, Planetary Detective

April 20, 2007
By Renee Dotson, LPI Staff

Molly McCanta looks like the girl next door. But don’t let appearances fool you; behind that all-American appearance lurks the mind of one of the most brilliant young researchers in the field of planetary science today. While many young women her age are passionate about rock bands, McCanta has a passion for another kind of rock . . . the kind that traveled from Mars to Earth and arrived in the form of a meteorite.

McCanta’s academic performance and demonstrated proficiency as a researcher earned her a spot in 2006 as a Urey Fellow at the Lunar and Planetary Institute in Houston, Texas. The prestigious Urey Fellowship Program is aimed at the postdoctoral level and recognizes excellence in research for scientists within five years of completion of their Ph.D. While at the Institute, McCanta was interviewed for a feature segment entitled “The Surface of Mars” that recently aired on The Futures Channel.

In the interview, McCanta not only explains the work she is doing, but conveys her enthusiasm for the knowledge that can be gained in the process.

You could say that McCanta is a detective of sorts. The current worldwide collection of rocks from Mars that have arrived in the form of meteorites totals only 37. McCanta’s goal is to study these rocks to glean information that will help us to understand the geological history of the Red Planet. With only 37 samples available, that’s quite a daunting task, but McCanta loves the challenge.

“Everyone knows we went to the Moon and that we brought back a lot of samples, but not very many people know that we have samples in hand from Mars. And we haven’t gone there; Mars gave them to us to look at,” explains McCanta.

At some point in the past, something hit Mars with enough force to create a crater and throw off material that traveled through space, arriving on Earth in the form of meteorites. Scientists know these meteorites came from Mars because of three very distinct pieces of evidence.

“First of all, we know these rocks are very young, so they had to have come from a planet that had volcanic activity into very near present time, something like the Earth, and that limits the number of planets in our solar system down to essentially Mars.” McCanta continues to explain that the other two pieces of evidence are the type of oxygen contained in the rocks, which is not the type of oxygen found on Earth, and the gas bubbles trapped within them, which match the gas compositions measured by the Viking landers when they arrived on the martian surface in the 1970s.

One of the goals of McCanta’s research is to determine where on Mars a meteorite came from, or where there are rocks of similar type on Mars. “We may never be able to say this is the exact crater that this certain meteorite came from, but what we can say is that this region has a very similar composition to these meteorites that we have down on Earth, and we know the conditions they formed under so we can say something then about the geology of that region on Mars.”

And the challenge? Trying to determine the geology of a planet with only 37 samples to work with. After all, if someone were to give you 37 randomly distributed rocks from the Earth and ask you to tell them how the Earth formed, what its geologic history was, and what it’s doing today, that would be a very difficult assignment. So that becomes an issue with working with Mars or any other type of planet. Because we have only a small amount of information to go on, scientists like McCanta try and glean every little bit they can from the rocks they study. “All the assumptions we make based on these 37 rocks, it will be very interesting to see if they hold up when we actually send people there who can walk around the surface and pick up whatever they want.”

While the surface of Mars obviously has similarities to what the Earth was in some respects — large volcanos, huge valleys that appear to have been channelized with outflows of water — it clearly had a very different geologic history. The attempt to understand what goes on there will help us to better understand our own planet. More importantly — and one of the major goals of NASA — is to continue the search for places where other forms of life might have developed.

One of the most refreshing things about listening to McCanta talk about her work is the excitement and animation she conveys. “The most fun thing about my work is when we get a new meteorite and I’m one of the first people to actually look at it. Here I have a piece of rock that no one else has looked at that’s from another planet, and it’s up to me to figure out how it got to be here and what it might tell us about that place.”

Her enthusiasm is contagious, but true to form, she’s not content to rest on her laurels and simply perform her research, but has a passion for inspiring the next generation of detectives as well. She ends the interview with an impassioned plea to those who might follow in her footsteps: “Missions can take decades to produce and to actually fly. Young people are encouraged to get involved at the early stages, because they’re the ones who are actually going to be the scientists when these spacecraft get there and start producing data and sending it back to Earth.”